Browsing by Author "Hsu, CM"

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A CMOS dual-mode RF front-end receiver for GSM and WCDMA
(2004)
Ko, CL
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Kuo, MC
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Hsu, CM
;
Kuo, CN
;
交大名義發表
A dual-mode, triple-band RF front-end receiver for GSM900, DCS1800 and WCDMA is presented. Because the system concepts of GSM and WCDMA are totally different from the standards, the chip uses low-IF and zero-IF receiver architecture for GSM and WCDMA, respectively. This chip consists of three parallel LNAs and down-conversion mixers with on-chip LO I/Q generations. The receiver front-end has been implemented in a standard 0.25um CMOs process and consumes about 30-mA from a 2.7-V power supply for all modes. The measured double-side band noise figure and voltage gain are 3dB, 36dB for the GSM900, 5.9dB, 31dB for the DCS1800, and ?-dB, 17.2dB for the WCDMA, respectively.
A novel approach for optimizing the optical performance of the broadband tap coupler
(2003-02-20)
Hsu, CM
;
Su, CT
;
Liao, D
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工業工程與管理學系
;
Department of Industrial Engineering and Management
An integrated approach using neural networks, exponential desirability functions and genetic algorithms to optimize parameter design problems with multiple responses is presented. The proposed approach aims to identify the input parameter settings to maximize the overall minimal satisfaction level with respect to all the responses. The proposed approach is illustrated by optimizing the fused process parameters created during fused biconic taper coupler development to improve the performance and reliability of a 1% (1/99) single-window broadband tap coupler. The proposed solution procedure was implemented on a Taiwanese manufacturer of fibreoptic passive components. The implementation results demonstrate the practicability of the method. Comparison analysis revealed that the proposed procedure outperformed the traditional Taguchi method in resolving multi-response parameter design problems.
Angiotensin I-converting enzyme ACE 2350*G and ACE-240*T-related genotypes and alleles are associated with higher susceptibility to endometriosis
(2005-01-01)
Hsieh, YY
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Chang, CC
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Tsai, FJ
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Hsu, CM
;
Lin, CC
Endometriosis displays features similar to malignancy, ranging from neovascularization to local invasion and aggressive spread to distant organs. The altered vascular-related genes might be related to the development of endometriosis. This study investigates whether angiotensin I-converting enzyme (ACE) *A2350G and A-240T gene polymorphisms could be used as markers of susceptibility in endometriosis. Women were divided into two groups: (1) endometriosis group (n=150) and (2) non-endometriosis group (n=159). Genomic DNA was obtained from peripheral leukocytes. ACE A2350G and A-240T gene polymorphisms were amplified by PCR and detected after restriction enzyme digestion with BstUI and XbaI. Genotypes and allelic frequencies in both groups were compared. We observed that genotype distribution and allele frequency of ACE 2350 and ACE-240 gene polymorphisms in both groups were significantly different. Proportions of ACE 2350*A homozygote/heterozygote/G homozygote in both groups were: (1) 66.7/29.3/4% and (2) 96.2/3.1/0.7%. Proportions of ACE-240*A homozygote/heterozygote/T homozygote in both groups were: (1) 43.3/46/10.7% and (2) 62.9/35.8/1.3%. We concluded that ACE 2350*G and ACE-240*T-related genotypes and alleles are associated with higher susceptibility to endometriosis. ACE A2350G and A-240T gene polymorphisms might be associated with endometriosis development.
Comparisons on properties and growth mechanisms of carbon nanotubes fabricated by high-pressure and low-pressure plasma-enhanced chemical vapor deposition
(2004-11-01)
Lin, CH
;
Lee, SH
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Hsu, CM
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Kuo, CT
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材料科學與工程學系
Effects of plasma pressure and the presence of nitrogen on growth of carbon nanotubes (CNTs) and their properties were studied by using microwave plasma chemical vapor deposition (MPCVD) (pressure=600-3300 Pa) and electron cyclotron resonance chemical vapor deposition (ECR-CVD) (pressure=0.3-0.6 Pa) systems. CH4/H-2 and CH4/N-2 were used as source gases, and Co as the catalyst. The structures and properties of CNTs were characterized by using field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Raman spectra, and field emission I-V measurements. The results show that. CNTs made by higher plasma pressure system have a higher growth rate (typically 1-3 mum/min), smaller tube diameter, better field emission properties, and better tube quality. The growth rate is related to the availability of carbon source. The morphology change from spaghetti-like to well-aligned CNTs is discussed in terms of directed ions. The change in field emission properties is reasoned in terms of geometric enhancement factor and screening effect for different tube morphologies. The presence of nitrogen plasma can have the following effects: increasing tube diameter, increasing straightness of CNTs, forming of bamboo-like CNTs, deterioration of field emission properties, and shifting of Raman peak toward lower-frequency side (or increasing residual tensile stress). (C) 2004 Elsevier B.V. All rigths reserved.
Forming silicon carbon nitride crystals and silicon carbon nitride nanotubes by microwave plasma-enhanced chemical vapor deposition
(2002-06-17)
Chang, HL
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Hsu, CM
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Kuo, CT
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材料科學與工程學系
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Department of Materials Science and Engineering
Catalyst-assisted silicon carbon nitride (SiCN) nanotubes and SiCN crystals are prepared. The SiCN nanotubes and SiCN crystals are formed by gaseous sources of CH4/N-2/H-2 and CH4/N-2, respectively, and using solid Si columns arranged symmetrically around the specimen as additional Si sources. The formation of the tubular structure is related to the ambient of process that includes H-2 gas, which is considered to delay the action of the so-called catalyst poisons and keep the tube end open during growth. Analysis shows that the SiCN crystals exhibit tetragonal or hexagonal shapes with sizes of about several microns, and multibonding structures. In contrast, the SiCN tubes are randomly orientated with various diameters, and graphitelike structure. The growth mechanisms of SiCN crystals and SiCN nanotubes are discussed. (C) 2002 American Institute of Physics.
Growth behavior and interfacial reaction between carbon nanotubes and Si substrate
(2004-07-01)
Hsu, CM
;
Lai, HJ
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Kuo, CT
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The effect of the interfacial reaction of Co catalyst with a Si substrate on growth of carbon nanotubes (CNTs) was investigated. Well-aligned multiwall CNTs (MWCNTs) were synthesized and applied barrier layers by microwave plasma-enhanced chemical vapor deposition (MPECVD). Growth proceeded in a flowing mixture of H-2, CH4, and N-2 as precursors at a temperature of 600 degreesC and a -200 V substrate bias; Co was sputtered as the catalytic material. Transmission electron microscopy (TEM) and x-ray diffraction were employed to examine the growth behavior of CNTs on Si (100) substrates on which Co had been deposited by MPECVD. The TEM results indicate that discrete conical CoSi2 layers with {111} and (100) faceted interfaces were formed on a Si (100) substrate during CNTs growth. Direct evidence that the growth is by tip growth and base growth is presented. The results show that well-aligned CNTs exhibit a significant emission current. The field emission characteristics of CNTs are contributed to the relationship between the application of different barrier layers and the growth mode of CNTs. (C) 2004 American Vacuum Society.
Growth of the large area horizontally-aligned carbon nanotubes by ECR-CVD
(2002-12-02)
Hsu, CM
;
Lin, CH
;
Chang, HL
;
Kuo, CT
;
材料科學與工程學系
For potential applications of carbon nanotubes (CNTs) as connectors in microelectronic devices, the process to synthesize the large area horizontally-aligned CNTs on 100 mm (4 inch) Si wafers was developed, using electron cyclotron resonance chemical vapor deposition, with CH, and H, as the source gases and Co as the catalyst. The results show that vertical and horizontal CNTs can be obtained by manipulating the electric field applied on the substrate and flow direction of the gases. In the present deposition conditions, the horizontal CNTs show better field emission properties than vertical CNTs. This may be due to the blocking effect of catalysts at the tips and to the diminishment of the effective emission area from defects of vertical CNTs body. (C) 2002 Elsevier Science B.V. All rights reserved.
Interleukin-2 receptor beta (IL-2R beta)-627*C homozygote but not IL-12R beta 1 codon 378 or IL-18 105 polymorphism is associated with higher susceptibility to endometriosis
(2005-08-01)
Hsieh, YY
;
Chang, CC
;
Tsai, FJ
;
Hsu, CM
;
Lin, CC
Multi-objective machine-component grouping in cellular manufacturing: a genetic algorithm
(1998-03-01)
Hsu, CM
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Su, CT
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工業工程與管理學系
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Department of Industrial Engineering and Management
The cellular manufacturing system (CMS) is an important group technology (GT) application. The first step of CMS design is cell formation, generally known as machine-cell formation (MCF) or machine-component grouping (MCG). A genetic algorithm (CA) is a robust adaptive optimization method based on principles of natural evolution and is appropriate for the MCG problem, which is an NP complete complex problem. In this study, we propose a GA-based procedure to solve the MCG problem. More specifically, this study aims to minimize (1) total cost, which includes intercell and intracell part transportation costs and machines investment cots; (2) intracell machine loading imbalance; and (3) intercell machine loading imbalance under many realistic considerations. An illustrative example and comparisons demonstrate the effectiveness of this procedure. The proposed procedure is extremely adaptive, flexible, efficient and can be used to solve real MCG problems in factories by providing robust manufacturing cell formation in a short execution time.
Multi-objective machine-part cell formation through parallel simulated annealing
(1998-08-01)
Su, CT
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Hsu, CM
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工業工程與管理學系
;
Department of Industrial Engineering and Management
Group technology (GT) is a manufacturing philosophy which identifies and exploits the similarity of parts and processes in design and manufacturing. A specific application of GT is cellular manufacturing (CM). The first step in the preliminary stage of cellular manufacturing system (CMS) design is cell formation, generally known as a machine-part cell formation (MPCF) or a machine-component grouping (MCG) problem. Simulated annealing (SA) is not only a highly effective and general random search method to obtain near-global optimal solutions for optimization problems, but also quite appropriate for the MPCF problem which is an NP complete, complex problem. In this study, we introduce modified SA with the merits of a genetic algorithm (GA), call parallel SA (PSA), and propose a PSA-based procedure to solve the MPCF problem. More specifically, this study aims to minimize (1) total cost which includes intercell and intracell part transportation cost and machine investment cost, (2) intracell machine loading unbalance and (3) intercell machine loading unbalance under many realistic considerations. The illustrative example, comparisons and analysis demonstrate the effectiveness of this procedure. The proposed procedure is extremely adaptive, flexible, efficient and can be used to solve real MPCF problems in factories by providing a robust manufacturing cell formation in a short execution time.
Root growth of multi-wall carbon nanotubes by MPCVD
(2005-01-03)
Hsu, CM
;
Lin, CH
;
Lai, HJ
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Kuo, CT
;
材料科學與工程學系
This work examines the relationships among the growth and interlayer reactions of carbon nanotubes (CNTs) to develop an effective process for controlling the nanostructure, orientation and characteristics of CNTs. Vertically oriented CNTs were successfully synthesized by microwave plasma chemical vapor deposition (MPCVD) with CH4/H-2 as source gases. Additionally, the Ti and SiO2 barrier layers and the Co catalyst were used in an experiment on the growth of CNTs on the Si wafer. Then, the SiO2 barrier layer was deposited by low-pressure chemical vapor deposition (LPCVD). The Ti barrier layer and Co catalyst films were deposited on the Si wafer by physical vapor deposition (PVD). The deposited nanostructures were characterized by scanning and transmission electron microscopy, the results of which reveal that the deposited MWCNTs were grown under the influence of a catalyst on Si substrates with or without a barrier layer, by MPCVD. Vertically gown, dense MWCNTs attached to a catalytic film demonstrate that various MWCNTs penetrated the root particles. The diameter of the root particles, of approximately in the order of 100 nm, is larger than those of the tube, 10-15 nm. The well-known model of the growth of CNTs includes base- and tip-root growth. The interaction between the catalytic film and the supporting barrier layer is suggested to determine whether the catalytic particles are driven up or pinned down on the substrate during the growth. (C) 2004 Elsevier B.V. All rights reserved.
Simultaneous optimisation of the broadband tap coupler optical performance based on neural networks and exponential desirability functions
(2004-06-01)
Hsu, CM
;
Su, CT
;
Liao, D
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
This study presents an integrated procedure using neural networks and exponential desirability functions to resolve multi-response parameter design problems. The proposed procedure is illustrated through optimising the parameter settings in the fused bi-conic taper process to improve the performance and reliability of the 1% (1/99) single-window broadband tap coupler. The proposed solution procedure was implemented on a Taiwanese manufacturer of fibre optic passive components and the implementation results demonstrated its practicability and effectiveness. A pilot run of the fused process revealed that the average defect rate was reduced to just 2.5%, from a previous level of more than 35%. Annual savings from implementing the proposed procedure are expected to exceed 0.5-1.0 million US dollars. This investigation has been extensively and successfully applied to develop optimal fuse parameters for other coupling ratio tap couplers.
The role of nitrogen in carbon nanotube formation
(2003-10-01)
Lin, CH
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Chang, HL
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Hsu, CM
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Lo, AY
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Kuo, CT
To examine the role of nitrogen, Co- and Ni-coated substrates were pretreated with three different gas compositions to compare the pretreated catalyst surfaces; the Fe, Co and Ni foils were subjected to carbon nanotube (CNT) growth experiments with CH4/H-2 and CH4/N-2 as source gases; the catalyst pretreatment plus the CNT growth experiments on Co- and Ni-coated Si substrates were carried out using both microwave plasma chemical vapor deposition and electron cyclotron resonance chemical vapor deposition (ECR-CVD) under different nitrogen-containing gases. The results show that the role of nitrogen may be summarized as follows: by comparing with hydrogen plasma, the bombardment energy of nitrogen plasma is greater. Therefore, the presence of nitrogen during CNT growth can keep the front catalyst surface clean and active to prolong surface passivation to enhance carbon bulk diffusion. The higher temperature due to higher bombardment energy of nitrogen plasma can promote agglomeration effects during catalyst pretreatment and the initial stage of CNT growth to produce larger size nano-particles. The presence of nitrogen is a favorable condition for formation of the bamboo-like CNTs, but not a necessary condition. Another favorable condition for formation of the bamboo-like CNTs is to deposit CNTs by ECR-CVD. (C) 2003 Elsevier Science B.V. All rights reserved.